JP5325831B2 - Polishing pad dressing method, substrate polishing method - Google Patents

Description

The present invention, dressing how the polishing pad dressing is brought into contact with the dresser to a polishing pad on the polishing table, to a board polishing method.

  In recent years, as semiconductor devices are highly integrated, circuit wiring is becoming finer and the distance between wirings is becoming narrower. In particular, in the case of photolithography having a line width of 0.5 μm or less, the depth of focus becomes shallow, so that a high flatness of the image plane of the stepper is required. As a means for flattening the surface of such a semiconductor wafer, a polishing apparatus that performs chemical mechanical polishing (CMP) is known.

  Conventionally, as shown in FIG. 1, this type of polishing apparatus includes a polishing table 102 that forms a polishing surface by attaching an upper surface polishing pad (polishing cloth) 100 and a substrate W such as a semiconductor wafer that is an object to be polished. A top ring 104 for holding is provided. The surface to be polished of the substrate W held by the rotating top ring 104 is pressed against the rotating polishing table 102 with a constant pressure, and the polishing surface of the substrate W is made flat and mirror surface while supplying abrasive liquid from the nozzle 106. Polishing. The polishing liquid is, for example, a solution obtained by suspending abrasive grains made of fine particles such as silica in an alkaline solution, which is a chemical / mechanical action that is a combination of chemical polishing action by alkali and mechanical polishing action by abrasive grains. The substrate W is polished by polishing.

  In order to regenerate the surface of the polishing pad 100 deteriorated by polishing, a dressing device having a dresser 108 is attached to the side of the polishing table 102 and the polishing of the polishing table 102 rotating the dressing surface of the rotating dresser 108 is performed. While pressing against the surface, the abrasive fluid and cutting chips adhering to the polishing surface are removed, and the polishing surface is flattened and dressed. A diamond dresser is mainly used as the dresser 108 for polishing and flattening the polished surface. Here, the uniformity of the polished surface after dressing greatly affects the subsequent polishing accuracy of the substrate W.

JP 2006-272549 A

  When the dresser 108 of the dressing apparatus is replaced, there is a problem that the pad cut rate of the polishing pad changes due to the difference in the dresser solids, and the polishing rate and the polishing profile change. Further, conventionally, when the dresser 108 of the dressing apparatus is replaced, the dresser 108 is pressed against the polishing pad 100 with a predetermined pressure to perform the running-in operation of the dresser. With this method, there is a problem that the polishing performance is adversely affected in the initial stage of polishing of the substrate W. There is also a problem in that the slurry during dressing adheres and accumulates on the dresser, which adversely affects the stability of the polishing performance.

The present invention has been made in view of the above points, and can keep the pad cut rate of the polishing pad constant at the time of changing the dresser, and can prevent the polishing rate and the polishing profile from being varied due to the solid difference of the dresser. dressing how, and to provide a substrate polishing method which can correct substrate polishing an object.

In order to solve the above problems, the present invention provides a polishing pad dressing method in which a dresser is brought into contact with a polishing pad on a polishing table to dress the polishing pad under predetermined dressing conditions, wherein the dresser has a radius on the upper surface of the polishing pad. The polishing pad is dressed while swinging in the direction, the polishing pad is divided into a plurality of zones, and the position of the dresser in the radial direction on the upper surface of the polishing pad in each zone is measured at the time of dressing. The polishing pad cut rate is measured, the polishing pad profile is obtained from the polishing pad cut rate, and the polishing pad profile is fed back to the dressing conditions.

As described above, when dressing the polishing pad with the dresser, the radial position of the dresser on the upper surface of the polishing pad in each zone is measured, the cut rate of the polishing pad at the position is measured, and the cut rate of the polishing pad is By obtaining a polishing pad profile and feeding back the polishing pad profile to dressing conditions, the pad cut rate during dresser replacement can be kept constant.

  The present invention also includes a polishing table provided with a polishing pad on the upper surface, a dresser, and a dresser drive control means for driving and controlling the dresser, and the polishing pad is brought into contact with the polishing pad under predetermined dressing conditions. A dressing device for a polishing pad to be dressed, provided with a cut rate measuring means for measuring the cut rate of the polishing pad by a dresser, and feeding back the cut rate of the polishing pad measured by the cut rate measuring means to the dresser drive control means, It is characterized by being reflected in conditions.

  As described above, the cut rate of the polishing pad measured by the cut rate measuring means is fed back to the dresser drive control means and reflected in the dressing conditions, whereby the pad cut rate at the time of dresser replacement can be kept constant.

  In the dressing apparatus for a polishing pad according to the present invention, the cut rate may be measured by measuring a change in torque current value of a polishing table drive motor that drives a polishing table, a change in torque current value of a dresser drive motor that drives a dresser, The cut rate is measured by any one or a combination of the positional changes of the contact surface of the polishing pad.

  Further, the present invention is a polishing pad dressing device comprising a polishing table having a polishing pad on the upper surface and a dresser, and dressing the polishing pad by bringing the dresser into contact with the polishing pad, the dresser covering the upper surface of the polishing pad. A dresser break-in device is provided that allows the dresser to break in a swing range outside the upper surface of the polishing pad.

  By providing the dresser break-in device for performing the dresser break-in in the dresser swing range as described above, the dresser break-in can be performed without affecting the polishing pad.

  According to the present invention, in the dressing device for the polishing pad, the dresser break-in device is provided with a cut rate measuring means for measuring the cut rate of the polishing pad.

  As described above, the dresser break-in device is provided with the cut rate measuring means for measuring the cut rate of the polishing pad, so that it is possible to know the end point (end point) of the dresser break-in operation.

  Further, the present invention is characterized in that the dressing apparatus for a polishing pad is provided with dresser life judging means for judging the dresser life based on the cut rate of the polishing pad measured by the cut rate measuring means.

  By providing a dresser life judging means that judges the dresser life based on the cut rate of the polishing pad as described above, it is possible to replace the dresser when the dresser life reaches, so that the polishing pad is in an optimum condition for polishing. Can be maintained.

  Further, the present invention provides a dressing device for a polishing pad, wherein the dresser running-in device is provided with torque current measuring means for measuring a torque current value of a dresser driving motor that drives the dresser, and the dresser running-in operation is performed from the measured torque current. An end point detecting means for detecting the end point is provided.

  In the polishing pad dressing apparatus according to the present invention, a cleaning means for cleaning the dressing surface of the dresser during a dresser running-in operation by the dresser running-in apparatus is provided.

  As described above, cleaning means for cleaning the dresser's dressing surface is provided during the dresser's break-in operation, so it is possible to remove the slurry and solid matter adhering to the dresser during dressing, and the slurry and solid matter are deposited on the dresser. Can be prevented.

  The present invention also includes a polishing table provided with a polishing pad on the upper surface, a dresser, and a dresser drive control means for driving and controlling the dresser, and the polishing pad is brought into contact with the polishing pad with a predetermined pressing force. A dressing device for a polishing pad for dressing a pad, wherein the dresser is mounted on a dresser arm so that the upper surface of the polishing pad is oscillated in a radial direction by a dresser turning mechanism, and the dresser has a radial direction on the upper surface of the polishing pad. A dresser position measuring means for measuring the position, a cut rate measuring means for measuring the cut rate of the polishing pad by the dresser, and a cutting rate measuring means in each zone measured by the dresser position measuring means by dividing the polishing pad into a plurality of zones. From the measured polishing pad cut rate, And a polishing pad profile measuring means for obtaining a profile, characterized in that the control means is provided for feeding back the polishing pad profiles measured in the polishing pad profile measuring means dresser drive control means.

  As described above, for the polishing pad divided into a plurality of zones, the polishing pad profile measuring means for measuring the profile of the polishing pad by measuring the cut rate in each zone is provided. And the polishing pad can be dressed in a manner adapted to the actual profile. The polishing pad may be divided into a plurality of zones in the radial direction.

  According to the present invention, in the dressing apparatus for a polishing pad, the dresser turning mechanism is driven by a motor to swing the dresser arm, and the dresser position measuring means is configured by the number of pulses supplied to the motor. The position of the upper surface of the polishing pad in the radial direction is measured. As the position control motor or pulse motor, for example, a stepping motor or a servo motor can be used.

  The present invention also provides a polishing table provided with a polishing pad on the upper surface, a dresser, dresser drive control means for driving and controlling the dresser, a top ring for holding a substrate to be polished, and a top for driving and controlling the top ring. A ring drive control means is provided for dressing the polishing pad by bringing a rotating dresser into contact with the polishing pad with a predetermined pressing force and a substrate to be polished held by a top ring rotating on the dressed polishing pad. A substrate polishing apparatus that abuts with a pressing force and polishes the substrate to be polished. The dresser is mounted on a dresser arm and the upper surface of the polishing pad is swung in a radial direction by a dresser turning mechanism. A dresser position measuring means for measuring a radial position on the upper surface of the pad, and a polishing pad by the dresser. The profile of the polishing pad is calculated from the cut rate of the polishing pad measured by the cut rate measuring means in each zone measured by the dresser position measuring means and the cut rate measuring means for measuring the cut rate of the die and the polishing pad divided into a plurality of zones. Polishing pad profile measuring means for measuring, first control means for feeding back the polishing pad profile measured by the polishing pad profile measuring means to the dresser drive control means, and polishing substrate profile measurement for measuring the profile of the polishing surface of the substrate to be polished. And a second control means for feeding back the substrate profile measured by the substrate profile measuring means to the top ring drive control means.

  As described above, with respect to the polishing pad divided into a plurality of zones, the cut rate was measured in each zone, thereby measuring the polishing pad profile and the polishing pad profile measuring unit. The first control means for feeding back the polishing pad profile to the dresser drive control means, the substrate profile measuring means for measuring the polishing surface profile of the substrate to be polished, and the substrate profile measured by the substrate profile measuring means to be polished. Since the second control means for feeding back to the top ring drive control means is provided, the polishing of the substrate and the dressing of the polishing pad can be performed in a form adapted to the actual polishing pad file based on the polishing pad profile. , Can increase the accuracy

  In the substrate polishing apparatus according to the present invention, the dresser turning mechanism is driven by a position control motor or a pulse motor to swing the dresser arm, and the dresser position measuring means is a position control motor or a pulse motor. The position of the dresser in the radial direction on the upper surface of the polishing pad is measured by the number of pulses supplied to.

  The present invention also provides a polishing table provided with a polishing pad on the upper surface, a dresser, dresser drive control means for driving and controlling the top ring, a top ring for holding the substrate to be polished, and driving and controlling the top ring. A top ring drive control means is provided, and a dresser rotating on the polishing pad is brought into contact with a predetermined pressing force to dress the polishing pad, and the substrate to be polished held by the rotating top ring is pressed against the dressed polishing pad. The polishing apparatus is a substrate polishing apparatus that polishes the substrate to be polished while being in contact with the dresser. The dresser is mounted on a dresser arm, and the upper surface of the polishing pad is swung in the radial direction by a dresser turning mechanism. A holding surface for holding the polishing substrate, the holding surface being divided into a plurality of regions; The dresser position measuring means for measuring the radial position on the upper surface of the polishing pad, the cut rate measuring means for measuring the cut rate of the polishing pad by the dresser, and the polishing pad were divided into a plurality of zones and measured by the dresser position measuring means. Based on the polishing pad profile measuring means for obtaining the polishing pad profile from the cutting rate of the polishing pad measured by the cut rate measuring means in each zone and the polishing pad profile measured by the polishing pad profile measuring means, the substrate to be polished is polished to the polishing pad. And a control means capable of controlling the pressing force in each zone of the holding surface of the top ring in accordance with the thickness of the polishing pad.

  In addition, the present invention dresses the polishing pad by bringing a rotating dresser into contact with the polishing pad provided on the upper surface of the polishing table with a predetermined pressing force, and holds the dressing pad held by the rotating top ring on the dressed polishing pad. A substrate polishing method for polishing a substrate to be polished by pressing the polishing substrate while pressing the polishing substrate, wherein the dresser dresses the polishing pad while swinging the upper surface of the polishing pad in the radial direction, and the top ring has a plurality of regions. The substrate to be polished is held on a holding surface divided into a plurality of zones, the polishing pad is divided into a plurality of zones, the position of the dresser in each zone in the radial direction on the upper surface of the polishing pad is measured, and The polishing pad cut rate is measured, the polishing pad profile is obtained from the polishing pad cut rate, and the polishing pad profile is obtained. When the substrate to be polished held by the holding surface of the top ring is pressed against the polishing pad based on the foil, the pressing force in each zone of the holding surface of the top ring is controlled according to the thickness of the polishing pad. The polishing substrate is polished.

  In one aspect of the present invention, the cut rate of the polishing pad in each zone is a measured value of the cut rate at the center position of each zone of the polishing pad or a measured value of the cut rate measured at a plurality of measurement points in each thorn. Is an average value.

According to the present invention, when dressing a polishing pad with a dresser, the position of the dresser in each zone in the radial direction on the upper surface of the polishing pad is measured, the cut rate of the polishing pad at the position is measured, and the cut rate of the polishing pad is measured. The profile of the polishing pad is obtained from the above, and the profile of the polishing pad is fed back to the dressing conditions, so that the pad cut rate during dresser replacement can be kept constant. As a result, it is possible to prevent variations in the polishing rate and polishing profile of the polishing pad due to differences in the dresser solids.

  In addition, according to the present invention, by providing a dresser break-in device that breaks in the dresser, the dresser break-in can be performed without affecting the polishing pad.

  Further, according to the present invention, since the cleaning means for cleaning the dressing surface of the dresser is provided, it is possible to remove the slurry and solid matter adhering to the dresser during dressing, and the slurry and solid matter are deposited on the dresser. And the dresser can be maintained in a state suitable for dressing.

  Further, since the control means for feeding back the polishing pad profile measured by the polishing pad profile measuring means to the dresser drive control means is provided, the actual polishing pad profile can be made an ideal polishing pad profile.

  Further, a first control unit that feeds back the polishing pad profile measured by the polishing pad profile measurement unit to the dresser drive control unit, and a first control unit that feeds back the substrate profile to be polished measured by the substrate profile measurement unit to the top ring drive control unit. Since the second control means is provided, it becomes possible to make the substrate to be polished into an ideal substrate profile to be polished with the polishing pad dressed in the ideal polishing pad profile.

  Further, according to the present invention, when the substrate to be polished is pressed against the polishing pad based on the polishing pad profile measured by the polishing pad profile measuring means, each zone of the holding surface of the top ring corresponds to the thickness of the polishing pad. Since the control means for controlling the pressing force is provided, it is possible to polish the substrate to be polished appropriately according to the polishing pad profile. For example, feedback control is performed so that the pressing force is selectively increased in the region of the holding surface of the top ring corresponding to the portion where the thickness of the polishing pad is thin as compared with the region of the other holding surface.

  Further, according to the present invention, when the substrate to be polished held by the holding surface of the top ring is pressed against the polishing pad based on the measured polishing pad profile, each of the holding surfaces of the top ring corresponding to the thickness of the polishing pad Since the substrate to be polished is polished by controlling the pressing force in the zone, it is possible to polish the substrate to be polished appropriately according to the polishing pad profile. For example, feedback control is performed so that the pressing force is selectively increased in the region of the holding surface of the top ring corresponding to the portion where the thickness of the polishing pad is thin as compared with the region of the other holding surface.

It is a figure which shows the structural example of the grinding | polishing apparatus provided with the conventional dressing apparatus. It is a sectional side view which shows the schematic structural example of the grinding | polishing apparatus provided with the dressing apparatus which concerns on this invention. It is a top view which shows the schematic structural example of the grinding | polishing apparatus provided with the dressing apparatus which concerns on this invention. It is a figure which shows the schematic structural example of the dresser break-in apparatus of the dressing apparatus which concerns on this invention. It is a figure which shows the normal state of the dresser break-in apparatus of the dressing apparatus which concerns on this invention. It is a figure which shows the dresser running-in state of the dresser running-in apparatus of the dressing apparatus which concerns on this invention. It is a figure which shows the dresser washing | cleaning state of the dresser break-in apparatus of the dressing apparatus which concerns on this invention. It is a figure which shows the dresser standby state of the dresser running-in apparatus of the dressing apparatus which concerns on this invention. It is a figure which shows the measurement procedure of the profile of a polishing pad by the dressing apparatus which concerns on this invention. 1 is a conceptual diagram of a substrate polishing apparatus according to the present invention. It is a longitudinal section showing a schematic structure of a top ring used for a substrate polisher concerning the present invention. It is a figure which shows the processing flow for reflecting the dressing profile of the measured polishing pad in grinding | polishing of a to-be-polished substrate in the board | substrate polish apparatus which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. 2 and 3 are diagrams showing a schematic configuration of a polishing apparatus provided with a dressing apparatus according to the present invention. FIG. 2 is a side sectional view and FIG. 3 is a plan view. The polishing apparatus includes a polishing table 1, a top ring (not shown) that holds a substrate such as a semiconductor and presses it toward a polishing pad 4 attached to the upper surface of the polishing table 1, and an upper surface of the polishing pad 4. A dresser 3 for dressing is provided. The polishing table 1 is connected to a motor 7 and rotates around its axis as indicated by an arrow A.

  The dresser 3 is connected to a motor 14 via a power transmission mechanism 15 such as a gear, and is also connected to a lifting cylinder 16. As a result, the dresser 3 moves up and down as indicated by an arrow B, presses the dresser 3 against the polishing pad 4 with an arbitrary pressure, and rotates around its axis as indicated by an arrow C. The dresser 3 is connected to a dresser shaft 8, and diamond particles (not shown) are fixedly held on the metal layer 9 on the lower surface thereof by metal plating or the like. Above the polishing table 1, a dressing solution supply nozzle 5 that supplies a dressing solution (mainly pure water) is disposed on a polishing pad 4 attached to the upper surface of the polishing table 1. The motor 14 and the lift cylinder 16 are driven and controlled by a drive control device (not shown) under any dressing conditions (pressing force of the polishing pad 4 of the dresser 3, rotation speed of the dresser 3, etc.). .

  The dresser 3 includes a dresser arm 2 that swings (turns) as indicated by an arrow D by a turning mechanism 6 around a swing center O of a swing shaft (not shown). The turning mechanism 6 includes gears 6-1 and 6-2 and is driven by a motor 29. As the motor 29, a position control motor or a pulse motor can be used. For example, a servo motor or a stepping motor can be used. The diamond pad held on the metal layer 9 on the lower surface of the dresser 3 is pressed against the upper surface of the polishing pad 4, and the polishing table 1 and the dresser 3 are rotated so that the polishing pad 4 and the dresser 3 move relative to each other. The upper surface of 4 is shaved, and the upper surface of the polishing pad 4 is sharpened and repaired. Further, dresser position measuring means (not shown) for detecting the radial position of the upper surface of the polishing pad 4 of the dresser 3 by the number of pulses supplied to the motor 29 is provided. In the above-described example, the dresser arm 2 is swung (turned) in the radial direction of the polishing pad 4 as shown by the arrow D in the turning mechanism 6. However, the moving mechanism that can move the dresser 3 in the radial direction of the polishing pad 4. If it is.

  An eddy current sensor 10 is embedded in the polishing table 1 to cause a high-frequency current to flow through the sensor coil to induce an eddy current in the metal layer 9 of the dresser 3 and to measure the thickness of the polishing pad 4 from the magnitude of the eddy current. It is. Since the polishing pad 4 is a dielectric material such as foamed urethane, for example, the eddy current induced in the metal layer 9 of the dresser 3 is small if the thickness is thick, and increases if the thickness is thin. Therefore, the thickness of the polishing pad 4 can be measured by measuring the magnitude of the eddy current induced in the metal layer 9. The wiring 18 connected to the output end of the eddy current sensor 10 passes through the polishing table 1 and the polishing table support shaft 1a and passes to the controller 12 via the rotary connector 11 provided at the shaft end of the polishing table support shaft 1a. It is connected. The controller 12 is connected to the display device 13. Thus, an eddy current type polishing pad thickness detection monitor is configured. A slip ring can be used instead of the rotary connector 11. In FIG. 2, the eddy current amount induced in the metal layer 9 of the dresser 3 is provided with the eddy current sensor 10 in one place on the polishing table 1 below the polishing pad 4. For example, as shown in FIG. The upper surface of the pad 4 may be divided into a plurality of zones in the radial direction, provided below the polishing pad 4 at the center position of each zone, and the thickness of the polishing pad 4 at the center position of each zone may be measured.

  According to the eddy current type polishing pad thickness detection monitor 17, an eddy current sensor 10 detects a change in the thickness of the polishing pad 4 in the metal layer 9 of the dresser 3, and the eddy current sensor 10 detects this change. The measured current value is displayed on the display device 13, and the thickness of the polishing pad 4 can be detected. The controller 12 detects the cut rate of the polishing pad 4 based on a signal from the eddy current sensor 10 and feeds it back to the dresser drive control device that controls the motor 14 and the lift cylinder 16 to perform dressing conditions (polishing of the dresser 3). This is reflected in the pad pressing force, the radial movement speed of the upper surface of the polishing pad of the dresser 3, the rotational speed of the dresser 3, and the like. For example, this is reflected in the pressing force pressing the polishing pad 4 of the dresser 3 by the elevating cylinder 16, the number of rotations of the dresser 3 by the motor 14, and the like.

  In the above example, the measurement of the cut rate of the polishing pad 4 by the dresser 3 is measured by the eddy current sensor 10, but the cut rate of the polishing pad 4 is measured by the torque of the motor 7 that drives (rotates) the polishing table 1. Changes in the current value, torque current of the motor 14 driving the dresser 3, position change of the contact surface of the polishing pad of the dresser 3 (this can be detected by measuring changes in the height position of the dresser 3 or these. Further, the radial direction of the upper surface of the polishing pad of the dresser 3 is detected by the number of pulses supplied to the motor 29 (position control motor or pulse motor) as described above. Any measuring means may be used as long as the position in the radial direction of the upper surface of the polishing pad 3 can be detected.

  In the polishing apparatus having the above-described configuration, when the dresser 3 is replaced, there is a problem that the degree of abrasion (pad cut rate) of the polishing pad 4 changes due to the solid difference of the dresser, and the substrate polishing rate and the polishing profile change. Conventionally, the dresser 3 is accustomed to the polishing pad 4 when the dresser 3 is replaced. However, this method has a problem of adversely affecting the polishing performance, particularly the substrate polishing in the initial stage of the substrate polishing. Therefore, here, as shown in FIG. 3, when the dresser 3 is replaced at the retracted position of the dresser 3 (the end of the swinging range of the dresser 3 outside the upper surface of the polishing pad 4), the dresser running-in device that performs the running-in operation of the dresser 3 is performed. 20 is provided.

  As shown in FIG. 4, the dresser break-in device 20 includes a dresser break-in portion 23 having a configuration in which a dresser break-in member 22 is attached to the upper surface of the base member 21. The dresser running-in portion 23 is supported by a dresser running-in portion support shaft 27, can be moved up and down as indicated by an arrow E by an elevating mechanism (not shown), and can be rotated as indicated by an arrow F. For the dresser break-in material 22, for example, a foamed polyurethane material having the same quality as the polishing pad 4 is used. The dresser break-in material 22 is provided with a large number of cleaning liquid injection holes 24 so that the cleaning liquid is supplied from a cleaning liquid supply path (not shown) provided in the base member 21 and is injected from each cleaning liquid injection hole 24. It has become. Further, a brush member 25 such as a nylon brush can be arranged in the radial direction passing through the center portion of the dresser break-in material 22. 4A is a side view of the dresser break-in device 20, and FIG. 4B is a plan view of the dresser break-in device 20. FIG.

  As shown in FIG. 5, the dresser break-in portion 23 is always immersed in the cleaning liquid Q in the cleaning liquid storage tank 26 and is in a wet state. In FIG. 5, reference numeral 28 denotes a sealing mechanism that prevents leakage of the cleaning liquid Q in the cleaning liquid storage tank 26. When the dresser 3 is replaced, as shown in FIG. 6, the dresser running-in portion 23 is raised toward the dresser 3 evacuated to a predetermined position directly above the dresser running-in portion 23 of the dresser running-in device 20. Press against the lower surface with a certain pressure. Then, the dresser running-in portion 23 is rotated as indicated by an arrow F, the dresser 3 is rotated as indicated by an arrow C, and the upper surface of the dresser running-in material 22 is scraped off by the relative movement of the dresser 3 and the dresser running-in portion 23. , Doing-in of the dresser 3 is performed. At this time, the pressing pressure and the rotational speed of the dresser break-in portion 23 are controlled by a controller (not shown). Here, both the dresser 3 and the dresser running-in portion 23 are rotated, but the dresser running-in portion 23 may be stationary.

  In the dresser running-in device 20, an eddy current sensor similar to the eddy current sensor 10 in FIG. 2 is provided in the base member 21 of the dresser running-in portion 23, and the eddy current sensor The thickness change of the dresser break-in material 22 is measured, and the cut rate of the dresser break-in material 22 is measured. The measured cut rate is compared with the normal cut rate of the dresser 3, and if it is normal, the break-in operation is terminated as the end point of the dresser break-in operation. If not, the dresser break-in unit 23 continues the break-in of the dresser 3 To adjust the pad cut rate of the dresser 3. The cutting rate of the polishing pad 4 of the dresser 3 is basically decreasing from the start of use of a new product to the end depending on the wear of the corners of the diamond particles. The rate of decrease of the rate is fast, and the slope of the rate of decrease of the cut rate becomes gentle at a certain point. When the slope becomes gentle, the end point of the dresser break-in operation is set.

  As a method of measuring the cut rate of the dresser break-in material 22, the torque current of a motor (not shown) that drives the dresser 3, the torque current of the motor that drives the dresser break-in portion 23, or a combination thereof can also be used. It can be measured. Further, a dresser height position sensor (not shown) for measuring the height position of the dresser 3 during dressing is provided, and the cut rate of the dresser break-in material 22 is measured from the output of the dresser height position sensor. Good.

When the running-in operation of the dresser 3 is finished, as shown in FIG. 7, a predetermined gap is provided between the lower surface of the dresser 3 and the upper surface of the dresser running-in material 22, and the metal layer 9 that holds and holds the diamond particles of the dresser 3 is formed. The dresser cleaning brush 25 is brought into contact with the lower surface, and a cleaning liquid (pure water, chemical liquid, a mixture of pure water, chemical liquid, and N ₂ ) q is sprayed from the cleaning liquid injection hole 24 of the dresser running-in material 22 of the dresser running-in portion 23. The lower surface of the metal layer 9 is cleaned. Thereby, deposits, such as a slurry adhering to the lower surface of the metal layer 9 of the dresser 3, can be removed.

  The dresser 3 which has been conditioned and has been cleaned is immersed in the cleaning liquid Q in the cleaning liquid storage tank 26 while the lower surface of the metal layer 9 of the dresser 3 is being polished while the polishing apparatus is polishing the substrate as shown in FIG. Then, the dresser cleaning brush 25 is brought into contact therewith, while the lower surface of the metal layer 9 is kept in a wet state, the dresser 3 is cleaned while rotating, and is put on standby. Thereby, the lower surface of the dresser 3 is maintained in a wet state and a clean state.

  The dresser 3 used for a long time for dressing the polishing pad 4 of the polishing apparatus has a reduced pad cut rate, and if the pad cut rate falls below a predetermined value, the dresser 3 has reached the end of its life and is replaced. . The dresser break-in device can also be used to determine the dresser life. The dresser running-in device 20 is provided with dresser life judging means for judging the dresser life from the cut rate of the dresser running-in material 22, dressing the dresser running-in material 22 with the dresser 3 used for dressing the polishing pad 4, and measuring the cut rate. The life of the dresser 3 is determined from the measured cut rate.

  When the running-in operation of the dresser 3 at the time of replacement is performed by the dresser running-in device 20, when the running-in operation proceeds, the torque current value of the motor 14 that drives the dresser 3 changes (for example, the torque current value gradually decreases and the running-in operation is performed). The torque current value may be monitored so that the end point (end point) of the break-in operation of the dresser 3 may be detected.

Dressing of the upper surface of the polishing pad 4 of the polishing table 1 by the dresser 3 is performed every time the polishing of one substrate is completed. This dressing operation is performed by pressing the rotating dresser 3 against the upper surface of the polishing pad 4 of the rotating table 1 with a predetermined pressure. At this time, the dresser 3 rotates about the oscillation center O as shown in FIG. The dressing surface of the dresser 3 is brought into contact with the upper surface of the polishing pad 4 and reciprocally swung (rotated) in the radial direction as indicated by an arrow D. One-time (one-step) dressing is performed by dressing by a plurality of reciprocating rocking motions of the dresser 3. Also, the profile (surface shape) of the polishing pad 4 by dressing is measured by dividing the upper surface of the polishing pad 4 into a plurality of zones in the radial direction as shown in FIG. 9 and polishing pads at predetermined points a to e in each zone. 4 is measured.

At this time, if the thickness of the polishing pad 4 at five points a to e is continuously measured by one reciprocating swinging motion of the dresser 3, high-speed data processing is required, and an expensive data processing device with high data processing speed. Is required. Therefore, here, dressing by the reciprocating rocking motion of the dresser 3 is performed once , and only one point a to e, that is, dressing by the reciprocating rocking motion of the dresser 3 is performed within one zone in a plurality of zones. Measure the thickness of the polishing pad 4 only at a predetermined point (for example, point a for dressing by the first reciprocating rocking motion, point b by dressing by the second reciprocating rocking motion, and by the third reciprocating rocking motion) The thickness of the polishing pad 4 is measured as dressing point c at the dressing), and one-step dressing consisting of dressing by a plurality of reciprocating rocking motions ( by five reciprocating rocking motions a to e in the figure) measures the thickness of the polishing pad 4 of all points a~e through dressing). Further, in order to prevent the influence of noise, the thickness of the polishing pad 4 at each point is measured a plurality of times, and the average value is taken as the thickness of the polishing pad 4 at each point. In the figure, the thickness of the polishing pad 4 at point a is taken a plurality of times, the average value is the thickness of point a, the thickness of the polishing pad 4 at point b is taken a plurality of times, and the average value is called the thickness of point b. Thus, the thickness of the polishing pad 4 at each point is taken a plurality of times, and the average value is taken as the thickness of the polishing pad 4 at each point.

  By repeating the thickness measurement at each point of the polishing pad 4 as described above, the thickness of the polishing pad 4 at a predetermined point in a plurality of zones can be measured by polishing and dressing a plurality of substrates. A profile is obtained. A plurality of sets are repeated and averaged to obtain a polishing pad profile, which is reflected in the polishing recipe. In the example of FIG. 9, by polishing and dressing five substrates, the thickness of the polishing pad 4 at each point a to e can be measured, and a profile of one polishing pad is obtained. This is repeated 3 sets (for 15 substrates), averaged and reflected as a polishing pad profile in the polishing recipe.

  FIG. 10 is a conceptual diagram of a substrate polishing apparatus according to the present invention. The dresser 3 rotating in the direction of arrow C abuts on the upper surface of the polishing pad 4 attached to the upper surface of the polishing table 1 rotating in the direction of arrow A with a predetermined pressing force, and the dresser arm 2 (see FIG. 3) swings. As shown by arrow D, the polishing pad 4 is dressed while reciprocating in the radial direction of the polishing pad 4. The upper surface of the polishing pad 4 is divided into zones Z1 to Z7 in a ring shape in the radial direction, and the positioner 3 is positioned at the center of each zone Z1 to Z7 during dressing is selected from a position control motor or a pulse motor. Detection is performed by the number of pulses supplied to the motor 29, and the thickness of the polishing pad 4 is measured. The position in the radial direction of the upper surface of the polishing pad 4 of the dresser 3 can be accurately measured by the number of pulses supplied to the motor 29. T1 to T7 indicate measured values of the thickness of the polishing pad 4 at the center of each zone Z1 to Z7.

  The dressing profile of the polishing pad 4 is measured from the measured values T1 to T7 of the thickness of the polishing pad 4 in each of the zones Z1 to Z7, and this profile is fed back to the drive control device that drives and controls the dresser 3. This is reflected in the pressing force of the polishing pad of the dresser 3, the radial movement speed of the upper surface of the polishing pad of the dresser 3, the rotational speed of the dresser 3, etc. Thereby, an ideal dressing profile of the polishing pad 4 can be obtained.

  Reference numeral 30 denotes a top ring that holds the substrate to be polished W on its lower surface and rotates in the direction of arrow G about a rotation axis (not shown). The top ring 30 is provided with a retainer ring 32 on the outer periphery of the lower end, and annular belt-shaped pressure chambers M1 to M4 each including a membrane 41 are provided inside the retainer ring 32. The lower surface of the membrane 41 is a holding surface that holds the substrate W to be polished. By adjusting the pressure in each of the pressure chambers M1 to M4, it is possible to control the pressing force to the polishing pad 4 of the substrate W to be polished that is in contact with that portion.

  As described above, the measured values T1 to T7 of the thickness of the polishing pad 4 in each of the zones Z1 to Z7 are obtained, and thereby the pressure controller provided for each fluid path communicating with each pressure chamber is controlled to control the membrane. Since the pressures of the pressure chambers M <b> 1 to M <b> 4 formed by 41 can be adjusted, the pressure of each pressure chamber can be distributed according to the thickness of the polishing pad 4. Therefore, an appropriate polishing profile of the substrate W to be polished that is not affected by the dressing profile of the polishing pad 4 can be realized. As an example, the pressure in the pressure chamber corresponding to the zone (region) where the measured value of the polishing pad 4 is small is selectively made higher than the zone (region) where the measured value of the other polishing pad 4 is large. As a result, the polishing amount of the substrate to be polished W can be made uniform, but the present invention is not limited to this. In short, according to the profile of the polishing pad 4, feedback control is performed in which the pressing force for each zone is variable in order to realize the polishing profile. When polishing is performed continuously, the pad profile changes with time, so that the pressing force can be controlled after adding this change as a consideration variable.

  The pressure in the pressure chamber corresponding to the zone (region) where the measured value of the polishing pad 4 is small is selectively made higher than the zone (region) where the measured value of the thickness of the other polishing pad 4 is large. Also, the dressing profile of the polishing pad 4 is fed back to the drive control device that drives and controls the dresser 3 as described above to obtain an ideal dressing profile of the polishing pad 4, and then the dressing profile of the ideal polishing pad 4 is obtained. Thus, by adjusting the pressure in the pressure chambers M1 to M4, a more appropriate polishing profile of the substrate W to be polished can be realized.

  FIG. 11 is a longitudinal sectional view showing a schematic configuration of a top ring used in the substrate polishing apparatus according to the present invention. The top ring 30 includes a cylindrical container-like top ring main body 31 and an annular retainer ring 32 fixed to the lower end of the top ring main body 31. An annular pressure sheet 33 is disposed inside the top ring body 31, and the pressure sheet 33 is sandwiched between the top ring body 31 and the pressure sheet support member 34 and supported on the inner peripheral lower surface of the top ring body 31. . A top ring drive shaft 35 is disposed at the center of the top surface of the top ring body 31, and the top ring body 31 and the top ring drive shaft 35 are connected by a universal joint 36. The universal joint portion 36 includes a bearing ball 37, and transmits the rotational force of the top ring drive shaft 35 to the top ring body 31 and a spherical bearing mechanism that allows the top ring body 31 and the top ring drive shaft 35 to tilt relative to each other. And a rotational force transmission mechanism (not shown). The top ring body 31 can be tilted with respect to the top ring drive shaft 35 and rotates by receiving the rotational force of the top ring drive shaft 35.

  A disc-shaped chucking plate 38 is disposed in a space defined by the top ring body 31 and the retainer ring 32, and the chucking plate 38 has a chucking plate holding member 39 on the lower surface of the pressure sheet 33. Is held through. The top ring body 31, the pressure sheet 33, and the chucking plate 38 form a pressure chamber M5 above the chucking plate 38. The pressurizing sheet 33 is made of an elastic body such as rubber, and the chucking plate 38 can move up and down by pressurizing and depressurizing the inside of the pressure chamber M5. The lower surface of the chucking plate 38 is a substrate holding surface that holds the substrate W to be polished.

  Annular membranes 41a, 41b, 41c, and 41d are disposed on the lower surface of the chucking plate 38 serving as a substrate holding surface. The upper end of the membrane 41 a is sandwiched between the chucking plate 38 and the annular membrane holder 51 and is attached to the center of the lower surface of the chucking plate 38. The upper end of the membrane 41b is sandwiched between the chucking plate 38 and the annular membrane holder 51 and attached to the outer peripheral side of the membrane 41a on the lower surface of the chucking plate 38. The upper end of the membrane 41c is attached to the outer peripheral side of the membrane 41b on the lower surface of the chucking plate 38 with the upper end portion sandwiched between the lower surface of the outer peripheral edge of the chucking plate 38 and the annular membrane holder 52. Pressure chambers M1, M2, M3, and M4 are formed by the membranes 41a, 41b, 41c, and 41d, the substrate to be polished W, and the chucking plate 38, respectively.

  Fluid passages 42, 43, 44, 45 are connected to the pressure chambers M1, M2, M3, M4, respectively, and the fluid passages 42, 43, 44, 45 are respectively pressure controllers P1, P2, P3, P4. Is connected to a compressed air source 48. The fluid passage 46 is also connected to the pressure chamber M5, and the fluid passage 46 is also connected to the compressed air source 48 via the pressure controller P5. S1, S2, S3, and S4 are sensors for detecting the flow velocity, pressure, and flow rate of the fluid (compressed air) flowing through the fluid passages 42, 43, 44, and 45, respectively.

  In the top ring 30 configured as described above, the substrate W to be polished held by the top ring 30 is controlled by controlling the amount of pressure air supplied from the compressed air source 48 through the fluid path 46 to the pressure chamber M5 by the pressure controller P5. The pressing force for pressing the entire upper surface of the polishing pad 4 can be controlled. Further, by controlling the amount of pressure air supplied from the compressed air source 48 to the pressure chambers M1, M2, M3, and M4 through the fluid passages 42, 43, 44, and 45 by the pressure controllers P1, P2, P3, and P4. The pressing force of the zone of the substrate W to be polished located on the lower surface of each pressure chamber M1, M2, M3, M4 can be controlled.

  Fluid (compressed air) flow velocity, pressure, and flow rate flowing through the fluid passages 42, 43, 44, and 45 are detected by the sensors S 1, S 2, S 3, and S 4, and the detection data D 1 is sent to the control unit 50. Various data D2 such as a polishing profile necessary for polishing the substrate W to be polished and a measured polishing pad profile are input to the control unit 50. The control unit 50 receives the various data D2 and sensors S1, S2, S3. From the detection data D1 detected in S4, the pressures of the pressure chambers M1, M2, M3, M4, and M5 necessary for polishing the substrate W to be polished to the target polishing profile are calculated and stored in the pressure chambers. The flow rate, pressure, and flow rate of the compressed air to be supplied are calculated, and control signals CS1, CS2, CS3, CS4, CS5 are sent to the pressure controllers P1, P2, P3, P4, P5, and the pressure controllers P1, P2, P3, The flow rate, pressure, and flow rate of the compressed air sent to each pressure chamber M1, M2, M3, M4, and M5 are controlled by P4 and P5.

  FIG. 12 is a diagram showing a processing flow for reflecting the measured dressing profile of the polishing pad to the polishing of the substrate to be polished in the substrate polishing apparatus according to the present invention. First, the required polishing profile of the substrate to be polished is input (step ST1). Next, dressing of the polishing pad 4 is performed (step ST2), the thickness of each zone of the polishing pad 4 is measured, and the thickness profile of the polishing pad 4 is obtained (measured) (step ST3). On the other hand, the substrate to be polished W is polished (step ST4), the polishing rate of the polished surface is measured, and polishing profile data is acquired (step ST5).

  The polishing pad thickness profile acquired in step ST3 is compared with the ideal polishing pad thickness profile, and the polishing profile acquired in step ST5 is compared with the ideal polishing profile (step ST6). Next, as a result of the comparison in step ST6, it is determined whether or not the difference from the ideal profile is within the target value. If the difference is within the target (Yes), the process is terminated. Calculations for changing the conditions and for changing the polishing conditions are executed (step ST8).

Dressing conditions based on the operation result (pressing pressure of the dresser 3 in each zone Z1~Z7 of the upper surface of the polishing pad 4, the rotational speed of the dresser 3, the velocity of the arrow D direction of the dresser-3, etc.) to change the (step ST9) Dressing the polishing pad. That is, the change of the dressing condition is fed back to the dresser drive control device. Further, the polishing conditions (pressures P1 to P4 of the pressure chambers M1 to M4 of the membrane 32) are changed based on the calculation result (step ST10), and the substrate to be polished is polished. That is, the change of the polishing condition is fed back to the top ring drive control device.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible.

DESCRIPTION OF SYMBOLS 1 Polishing table 2 Dresser arm 3 Dresser 4 Polishing pad 5 Dressing liquid supply nozzle 6 Turning mechanism 6-1 and 6-2 Gear 7 Motor 8 Dresser shaft 9 Metal layer 10 Eddy current sensor 11 Rotary connector 12 Controller 13 Display device 14 Motor 15 Power transmission mechanism 16 Elevating cylinder 17 Detection monitor 20 Dresser break-in device 21 Base member 22 Dresser break-in material 23 Dresser break-in part 24 Cleaning liquid injection hole 25 Dresser cleaning brush 26 Cleaning liquid storage tank 27 Dresser break-in part support shaft 28 Seal mechanism 29 Motor 30 Top ring 31 Top Ring Body 32 Retainer Ring 41 Membrane 41a to 41d Membrane 42 Fluid Path 43 Fluid Path 44 Fluid Path 45 Fluid Path 46 Fluid Path 48 Compressed Air Source 0 control unit 51 membrane holder M1~M5 pressure chamber P1~P4 pressure controller S1~S4 sensor

Claims (4)

A polishing pad dressing method for dressing a polishing pad under predetermined dressing conditions by bringing a dresser into contact with a polishing pad on a polishing table,
The dresser dresses the polishing pad while swinging the upper surface of the polishing pad in the radial direction,
The polishing pad is divided into a plurality of zones, and at the time of dressing, the position of the dresser in each zone in the radial direction on the upper surface of the polishing pad is measured, the cut rate of the polishing pad at the position is measured, and the polishing pad is cut. A polishing pad dressing method comprising: obtaining a polishing pad profile from a rate, and feeding back the polishing pad profile to the dressing conditions. In the dressing method of the polishing pad of Claim 1,
The cut rate of the polishing pad is a value obtained by averaging measured values of the cut rate at the center position of each zone of the polishing pad, or measured values of cut rates measured at a plurality of measurement points in each zone. A method for dressing a polishing pad. Dressing the polishing pad by bringing the rotating dresser into contact with the polishing pad provided on the upper surface of the polishing table with a predetermined pressing force, and pressing the substrate to be polished held by the rotating top ring on the dressed polishing pad A substrate polishing method for polishing the substrate to be polished while being in contact with the substrate,
The dresser dresses the polishing pad while swinging the upper surface of the polishing pad in the radial direction,
The top ring is configured to hold the substrate to be polished on a holding surface divided into a plurality of regions,
The polishing pad is divided into a plurality of zones, the radial position of the dresser on the upper surface of the polishing pad in each zone is measured, the cut rate of the polishing pad at the position is measured, and the cut rate of the polishing pad is calculated. Obtain the polishing pad profile,
Based on the polishing pad profile, when pressing the substrate to be polished held by the holding surface of the top ring against the polishing pad, the pressing force in each zone of the holding surface of the top ring is corresponding to the thickness of the polishing pad. A substrate polishing method comprising controlling and polishing the substrate to be polished. The substrate polishing method according to claim 3 , wherein
The cutting rate of the polishing pad in each zone is a value obtained by averaging the measured values of the cutting rate at the center position of each zone of the polishing pad or the measured values of the cutting rate measured at a plurality of measurement points in each zone. A method for polishing a substrate, comprising:

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